Viscous dampers comprise a housing secured to the crankshaft of an internal combustion engine, an inertia weight rotatably mounted in the housing and a viscous fluid retained between the weight and the housing to function as a damping and/or tuning medium. Seizing of the weight in the housing will ultimately damage the engine's crankshaft and attendant components, thus resulting in a costly overhaul of the engine. Such seizing normally occurs when the viscous fluid is heated to a sufficiently high temperature to change it to powder form.